1. Field of the Invention
The present invention relates to a multiple well template and process of drilling multiple subterranean wells utilizing the template, and more particularly, to such a template and process wherein the template is deformed, positioned within a subterranean well bore and expanded for use in drilling multiple wells.
2. Description of Related Art
Increasingly, well bores are being drilled into subterranean formations at an orientation which is purposely deviated from true vertical by means of conventional whipstock technology or a mud motor secured in the drill string adjacent the drill bit. In fractured subterranean formations, deviated wells are utilized to increase the area of drainage defined by the well within the subterranean formation, and thus, increase production of hydrocarbons from the subterranean formation. An inherent problem in utilizing a conventional whipstock to drill a deviated well is that both the depth and radial orientation of the whipstock is set when the whipstock is positioned in the well bore and cannot be changed without retrieving the whipstock from the well bore and changing the depth and/or radial orientation thereof.
In addition, wells drilled from offshore drilling platforms are usually deviated to increase the number of wells which can be drilled and completed from a single platform. Offshore drilling platforms which are utilized in deep water to drill and complete wells in a subterranean formation vary in size, structure, and cost depending upon the water depth and the loads in which the platform will be set. For example, a platform may be constructed to be supported in part by one leg or caisson which extends to the ocean floor or by as many as eight such legs or caissons. Costs of such offshore drilling platforms vary from approximately $5,000,000 to $500,000,000. Each offshore drilling platform is equipped with a set number of slots via which deviated wells can be drilled and completed through surface casing which is secured at the mudline by conventional techniques.
Due to the significant capital expenditure required for these offshore platforms, templates and processes for drilling and completing multiple wells via a single conductor, surface or intermediate casing have been developed. Although the templates which have been developed can be utilized to drill and complete wells into subterranean formations or zones of the same or varying depths, these templates are not designed to drill and complete conventional sized bores, e.g. 7 inches, from a well bore of a similar conventional size so as to maximize the production rate of fluid from the subterranean formation(s) and/or zone(s) and provide mechanical integrity and a hydraulic seal at the template. Thus, a need exists for apparatus and processes to drill and complete multiple subterranean wells of a conventional size from a well bore of a similar conventional size into a plurality of subterranean formations or zones. A further need exists for an apparatus and process to drill and complete multiple subterranean well bores at greater degrees of separation from each other thereby significantly increasing the area of drainage and thus enhancing hydrocarbon recovery from the well.
Accordingly, it is an object of the present invention to provide a deformed template and process for drilling and completing multiple subterranean wells having bore sizes which substantially correspond to the size of the bore from which the multiple wells are being drilled utilizing such template.
It is another object of the present invention to provide a process for expanding a multi well deformed template in situ.
It is a further object of the present invention to provide a deformed template and process for drilling and completing multiple wells from an already existing well bore once such template is expanded which is cost effective.
It is still another object of the present invention to provide a deformed template and process for drilling and completing multiple subterranean wells using such template wherein mechanical integrity and a hydraulic seal at the template are provided.
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, one characterization of the present invention may comprise a deformed template for drilling and completing multiple subterranean wells from a first casing which is positioned in a subterranean well bore. The template comprises a body having at least two tubulars, each of which are deformed to permit passage within the subterranean well bore but capable of being expanded upon application of suitable force, and means for securing the body to the first casing.
In another characterization of the present invention, a template is provided for drilling and completing multiple subterranean wells from a first casing which is positioned within a subterranean well bore. The template comprises a body and means for securing the body to the first casing. The body has a first end face and a plurality of axially extending bores therethrough which intersect the first end face. At least one of the axially extending bores being deformed for positioning within the subterranean well bore and capable of being expanded.
In yet another characterization of the present invention, a process is provided for drilling wells via a first casing which extends from the surface of the earth into a first subterranean well bore. The process comprises securing a deformed template having at least two tubulars which are deformed to the first casing, expanding each of the at least two tubulars, and drilling a second subterranean well bore through one of the at least two tubulars into a first subterranean formation.